to go to bed; to give sth to sb in authority; to take sb to the police or sb in authority because they have committed a crime; to give back sth that you no longer need
Oxford44% of films
to go to bed
it's time to turn in. Big day tomorrow at the race.
I think I'll turn in.
Oxford38% of films
to give sth to sb in authority
Did you turn in a paper on "Mein Kampf"?
Oxford6% of films
to take sb to the police or sb in authority because they have committed a crime
Oxford6% of films
to give back sth that you no longer need
Definitions from the Oxford Advanced Learner's Dictionary, 9th edition